Setting utility access covers

ABSTRACT

Apparatus and method of setting access covers to grade wherein the apparatus includes rubblizing bits and a vacuum, the first rubblizing bit having a central core with attached carriers for teeth to grind the underlying material into small pieces, a second rubblizing bit to rubblize below the ring of the access, a third bit for trimming a step for a T-lock, and a fourth bit for milling around an access ring for resurfacing and the steps of rubblizing down to the area of the bottom of the ring and sucking out the material by vacuum, settting the height of the ring and cover, trimming a step for a T-lock, and milling around the ring and cover a selected distance.

BACKGROUND OF THE INVENTION

1). Field of Invention

This invention relates to setting utility access covers to grade andmore particularly to apparatus for rubblizing the material around theutility access and a method for setting utility access covers to gradeincluding rubblizing material, removing the rubblized material andestablishing the proper position of a utility access cover whenrenovating, reconstructing or installing new access covers.

There are a number of utilities that are underground and that havecomponents that have to be accessed. Some of these components aremeters, valves and pipes, for example. Some require servicing orinspection underground by personnel. In this case, there must be amanhole with a sufficiently wide opening for a person. In othersituations, underground access by personnel is not required. In bothcases, it is often necessary to set the access cover to grade.

2). Related Art

The apparatus and method will first be described in connection withmanholes, and then with respect to other utility access covers,including small ones used for such things as water valves. Manholes areassociated with access to underground utilities. There are manydifferent sizes and construction of manholes, but all have a cover thatshould be set according to the grade of the surrounding material. Somehave standard components and sizes, such as sanitary sewer manholes insome parts of the United States. These manholes have a 24-inch (2-foot)diameter lid or cover and a ring that holds and supports the cover. Thering has an outside diameter of 25 ½ inches and a cylindrical outer bodywith a height between 4 inches and 8 inches. There are also invertedrings with 1-inch height. The ring, other than inverted rings, has acircular flange around the body near the bottom to support weight and tohold it in place. Not all rings have flanges. Nevertheless, for purposesof illustration, rings with flanges will be described. The ring sits onthe top surface of an eccentric cone that has an internal diameter of 2feet at the top and 4 feet at the bottom. The cone sits on a manholebarrel section. The barrel section has an inside diameter of 4 feet anda wall thickness of 5 inches. Above the barrel section the eccentriccone transitions from the 4-foot internal diameter of the barrel sectionto the 2-foot internal diameter at the top of the cone. The wallthickness of the cone varies from 6 inches at the top to 5 inches at thebottom where it mates with the barrel section. The barrel section restson a foundation that supports the components of the manhole and theutility to be accessed. Often times, one or more height adjusting ringsor material is positioned between the bottom of the ring and the topsurface of the cone to adjust the cover to grade so that it is even withand aligned with the surface of the roadway. Also, on occasion, when aroadway has a new layer of asphalt or concrete applied, the height ofthe cover is adjusted by placing height- adjusting rings between the topof the ring and the cover. There are other manholes that are larger andothers that are smaller than the standard sanitary sewer manhole. Forexample, manholes for communication lines or equipment are often 3 feetin diameter at the top. These other manholes also require the setting ofthe cover to grade when renovating a manhole, reconstructing a manholeor installing a new manhole.

Some manholes in areas of the United States and outside of the UnitedStates have an understructure made of brick instead of a preformedbarrel section or pipe. Generally, these understructures of brick orpipe have a side with steps in the structure or a ladder attached to theside for ease of access. Additionally, the step or ladder side of theunderstructure cooperates with a side of the eccentric cone to providethe ladder or steps to the top of the cone. The cone may also beconstructed with brick. Thus, the dimensions of the cone andunderstructure of a barrel section may vary from those set forth abovefor a particular municipality's standard sanitary sewer manhole. Thedimensions will be different for other sewer manholes, for other utilitymanholes and for those constructed of various materials, such as brick.

Access cover are often located in roadways and over time the position ofsurrounding material deteriorates so that bumps are encountered by thevehicles using the roadway. Sometimes the bumps are caused by holes orcracks in the material surrounding the cover. Other times the bumps arecaused by the surface of the cover not being aligned with the surface ofthe roadway or not level with the roadway. The cover may be tiltedrelative to the roadway or sit below the surface of the roadway becauseof deterioration in the housing supporting the ring and cover or in thematerial used during installation to bring the cover up to the desiredheight aligned with the roadway. Also, resurfacing the street may leavethe cover below the surface of the new roadway. In these cases, themanhole will either be renovated or reconstructed. The term renovationwill be used to cover both reconstruction and renovation.

The renovation of manholes is a time consuming and labor intensive job.Each time a manhole is to be renovated, traffic control has to be put inplace before work can begin. Thereafter, the material around the coverand ring has to be removed. One or more men, operating jackhammers andshovels, break through the roadway surface and the underlying material,down to the flange on the ring. The breaking up of asphalt roadway withjackhammers leaves a raised lip, commonly known as the “volcano effect”.Typically, the removal of material stops at the flange area of the ringThe height can then be adjusted or not. Also, often times when theheight of the cover needs adjusted, the removal continues down to thetop of the cone and a few inches below.

The roadway surface is typically asphalt or concrete. The material underthe roadway around the ring and upper part of the cone, is eitherasphalt, concrete or road base. Once the roadway material and underlyingmaterial is broken down and removed and the cover set to grade, if notalready at grade, the hole is filled with new material.

An adjustment of the height of the cover is done by using materialbetween the top of the cone and the bottom of the ring. Preformedmaterial, such as adjusting rings, do not provide incrementaladjustment, only a gross adjustment. Fine adjustment of the height ofthe cover is needed. The time to set up and do the work to renovate amanhole, without height adjustment, often averages between one to twohours or more. When height adjustment is required it takes anextraone-half to one hour. When there are a series of manholes, in aroadway that need adjusted and using the typical operation describedabove, between 4 and 5 covers are typically adjusted in a normalworkday. Time limitations are commonly in effect by local jurisdictionsso that traffic may be detoured only during certain hours. Thisdrastically reduces the time available to perform the necessary work.

The first installation of a ring and cover for a newly installed manholeor other utility access requires removal of a portion of the underlyingmaterial down to the top of the cone or the top of the riser sleeve forutility accesses that are not designed for personnel going underground.

Again, jackhammers are used to break up the material and shovels areused to remove the material. An improvement in this process is thecutting a plug out of the roadway by a rotary cutter, such as that madeby Stehr Baumaschinen GmbH. The cutter cuts out a plug that may beremoved mechanically by a scoop on a skidster or backhoe, for example.Once the plug (circular piece of roadway) is removed, the underlyingmaterial is loosened and shoveled out down to the top of the cone.

The top of the cone is covered with a steel plate to keep material outof the manhole. Similarly, the top of the riser for smaller access holesis covered with a plate. The plate is removed and the ring and cover areinstalled by using height- adjusting material to set the cover to grade.

A problem also exists when a roadway is to be resurfaced. A layer ofroadway is milled off or cut away. The milling machines are largedevices that cut down large widths of roadway. These machines are toolarge to maneuver around utility access covers and rings. Consequently,in the past, scoops or jackhammers and shovels have been used.

SUMMARY OF THE INVENTION

It is an overall object of this invention to reduce the time and laborto set access covers to grade. Where the adjustment is associated withrenovation, in place of jackhammers and numerous men on the jackhammersand shovels, a rubblizing bit is used with a prime mover. The bit ispowered hydraulically, pneumatically, or electrically from a machineoperated by one person. One such machine or prime mover for driving thebit and controlling the position of the bit is a skidster.

The bit has a cylindrical central core that has an inner diameterslightly larger than the outside diameter of the ring and a wallthickness sufficient for strength and durability. A plurality of teethare attached to the bottom surface of the core. One or more carriers ofrubblizing teeth are attached to the central core and the rubblizingteeth extend beyond the circumference of the central core a selecteddistance to rubblize the material around the ring and down to thedesired depth. Where the ring has a flange, this depth is down to theflange of the ring. Each carrier has a mounting plate at the top, whichfits in a slot in the central core, or fits on top of the central core.The mounting plate is either welded or bolted to the central core orpositioned between two mounting plates that are permanently attached tothe core to hold the carrier in place. The carrier further includes avertical portion or plate that determines the extension of the carrierfrom the mounting plate at the top to the rubblizing teeth at thebottom. An attachment plate is attached to the vertical plate at thebottom of the plate at a right angle to carry the rubblizing teeth. Apair of triangular pieces of metal, having a right angle that fitsbetween the vertical plate and the attachment plate, is welded betweenthe vertical plate and the attachment plate to strengthen the carrier ofthe rubblizing teeth. A plurality of teeth are attached to the bottomside of the attachment plate at selected distances from the verticalplate and the outside diameter of the central core. There is a first rowremote from the vertical plate consisting of a pair of teeth and theninside the outside pair of teeth is another pair of teeth. The outsidepair of teeth are slanted to the outside of the attachment plate to meetand cut the material before the outside edge of the attachment plateengages the material. Inside these pairs of teeth are 3 teeth that arestaggered at shorter distances from the vertical plate or central coreof the bit. Additionally the pairs of teeth are stepped down and are atthe greatest depth relative to bottom surface of the central core of thebit. Advantageously, there are three carriers with rubblizing teeth,spaced 120 degrees apart around the central core of the bit.

The inside diameter of the cylindrical central core is greater than theoutside diameter of the ring to provide sufficient clearance for ease ofrotation of the rubblizing bit to grind the material around and beyondthe ring. This inside diameter for typical access covers and rings forwater valves is 10 inches. This diameter nay be greater or lesserdepending on the size of the ring. Further, the inside diameter forsanitary sewer rings and covers is 27 inches. Again this diameter may begreater or lesser depending upon the outside diameter of the ring.

The method of setting existing utility access covers to grade will beexplained in connection with a sanitary sewer manhole for a particularmunicipality. The method is not limited to sanitary sewer manholes withpreformed cones and barrels, but applies to manholes made of othermaterial such as brick. The method also applies to manholes of othersizes and to smaller utility access covers.

The method of setting manhole covers to grade employs the followingsteps when an existing manhole is being renovated. First the trafficcontrol devices and person is set in place. Next the rubblizing bit isused and as it rotates it grinds and rubblizes the material around thering down to the flange. The third step is to vacuum the rubblizedmaterial, which may take place while the rubblizing bit is rotating orafter the bit has rubblized down to the flange. Once the material hasbeen rubblized, the bit is pulled out of the hole and the vacuuming iscompleted to completely remove the rubblized material. If the height ofthe cover does not need adjusted, the hole is filled with new materialto complete the renovation.

Additionally, with renovation a T-lock may be desired. If so, a step ismilled in the roadway surface out from the hole created by therubblizing bit to a selected distance and depth. The step is created byteeth on a milling carrier or trimmer. There are three carriers attachedto the top of a central core and spaced 120 degrees apart to mill orgrind the step. The central core may be the same core as used for therubblizing step or it may be a central core used solely for this purposeor a central core with a larger inside diameter used to rubblize thematerial below the flange. When a step is milled and the hole is filled,the filling material extends out to fill this step and to form themoisture resistant T-lock.

If the height of the cover relative to the surface of the roadway needsadjusting, then a second rubblizing step takes place. In the firstrubblizing step, the bit stops its downward movement when the teeth onthe bottom surface of the central core reach the top surface of thesteel flange on the ring. The rubblizing teeth are designed to cutthrough and rubblize concrete, asphalt and roadbase, but not steel. Thesecond rubblizing step is accomplished by a bit that has a cylindricalcentral core with an internal diameter slightly larger than the outsidediameter of the top surface of the cone in the manhole. The materialbelow the flange and to a few inches below the top of the cone isloosened and sucked out by a vacuum. Once the rubblized material isremoved, the ring and cover are lifted out of the excavation. Next allor part of the old leveling material, if any, is removed from the top ofthe manhole cone. A height-adjusting device is then employed.Preferably, this device does not have a set height but is adjustable andacts as a form for either concrete or asphalt around the device whileholding the ring at the desired height.

If the distance between the bottom of the ring and the top of the coneis 2 inches or greater, then a form called a Whirlygig is used to adjustthe proper height of the ring and cover. The Whirlygig is a form andapparatus for selecting and cutting the desired height of the form. Thisapparatus and system are disclosed in U.S. Pat. No. 5,934,820 grantedVernon W. Hinkle on Aug. 10, 1999 and U.S. Pat. No. 6,161,985 grantedHinkle et al on Dec. 19, 2000. The disclosures of these two patents areincorporated herein by this reference as though set forth in full. TheWhirlygig forms are available from Whirlygig Company, 2418 BishopCircle, Caldwell, Id. 83605 (www.whirlygigcompany.com).

The form is placed on the cone and an apparatus with arms that extend tothe roadway engages and references the roadway in three or more places.This establishes the final top surface of the form and the height andslope of the cover and the top of the ring. A cutting tool then cuts thetop portion of the form so that it can be removed. Next the top portionand the cutter are removed. Then the ring and cover are placed on thetop of the form. The excavation up to the top of the form is firstfilled with concrete. Then the remainder of the excavated hole is filledwith either asphalt or concrete.

If the distance between the bottom of the ring and the top of the coneis less than 2 inches, advantageously an inflatable donut shaped formwith Adjusting Ring and Leveller with three or more arms are employed.An inflatable donut shaped form and Adjusting Ring are made by StehrBaumaschinen GmbH and are available from Mountain Valley Equipment, 64725 Road, Grand Junction, Colo. 81505. First the ring is attached to theholder of the Adjusting Ring. Then the ring and Adjusting Ring areplaced over the excavated hole with the ring hanging above the top ofthe cone. The ring is centered over the cone and the top of the ring isadjusted relative to the roadway by leveling the arms of the AdjustingRing so that the top of the ring and the cover will be on grade with theroadway. The inflatable donut is then placed inside the ring and extendsdown inside the top of the cone. The donut is inflated inside the ringand cone and provides a surface between the bottom of the ring and thetop of the cone as a form for concrete to establish the height and tohold the ring at the established height above the cone. The inflateddonut forms a seal at the bottom of the ring and at the top of the coneto prevent the filler material, typically a concrete material, fromseeping into the manhole cone. A T-lock in the roadway around themanhole may also be used when the cover and ring height is adjusted. Themilling or trimmer bit is used with the first or the second rubblizingbit in the first or second rubblizing step or as a separate trimmer bitmounted on its own central core.

The above apparatus and steps of the method are applicable to thesetting of manhole covers to grade for the initial installation of aring and cover on earlier installed understructure (barrel section orpipe and base) and eccentric cone. In this application, a coring bit islocated above the cone and cuts out a circular section of the roadway.This circular section or plug is lifted out and discarded. In newconstruction of a manhole, the cone is covered with a plate before thehole over the cone is filled and the road surface laid down. Thus, theexcavation goes down to the plate so that it may be removed. Theunderlying material down to the top of the cone is sucked out by vacuum.If loosening of the material is required, a lightweight jackhammersupplied with pressurized air from the vacuum truck is used.

After the plate is removed, the distance between the top of the cone andthe surface of the roadway is determined. This distance dictates thetype and height of ring to be used and the height-adjusting device to beused. The height adjusting device is advantageously, either a Whirlygigform or an inflatable donut. Other height adjusting devices may be used.

If a T-lock is to be included, a trimmer bit is used to cut a step inthe roadway at the same time as cutting the plug or at a different time.

A rubblizing bit or trimmer bit is also useful when resurfacing aroadway. The time consuming process of breaking up the material with ajackhammer and removal with a shovel or scooping out a desired depthwith a mechanical device is very inefficient. A trimmer bit having areach greater than the bit for milling a T-lock is used. The bit has acentral core that fits around the ring and grinds down into the materialaround the ring to stabilize and position the trimmer bit. The bitgrinds or mills the roadway down a desired depth, which is typically 11/2 inches or 2 inches for resurfacing.

Objects, features and advantages of this invention will become apparentfrom a consideration of the foregoing and the following description, theappended claims and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional elevation view of a manhole with a properlypositioned cover using asphalt;

FIG. 2 is a cross-sectional elevation view of a manhole with a properlypositioned cover using concrete;

FIG. 3 is a top plan view of a properly positioned cover with sectionlines 2-2 for the cross sectional views of FIG. 1 and FIG. 2;

FIG. 4 is a cross-sectional elevation view of the top portion of amanhole with the cover being misaligned with the roadway, in accordancewith the present invention;

FIG. 5 is a top plan view of deteriorated road surface around a manholecover, in accordance with the present invention;

FIG. 6 is a perspective view of the rubblizing bit attached to a machinefor controlling the position and operation of the bit, in accordancewith the present invention;

FIG. 7 is an enlarged view of the rubblizing bit with part of thesupporting structure removed, in accordance with the present invention;

FIG. 8 is a bottom plan view of the rubblizing bit, in accordance withthe present invention;

FIG. 9 is a top plan view, partially cut away, of the rubblizing bitwith the carrier placed in slots in a central core and held in place byplates welded to the central core, in accordance with the presentinvention;

FIG. 10 is a cross-sectional view of the right rear quarter of arubblizing bit, in accordance with the present invention;

FIG. 11 is a bottom plan view of a carrier for rubblizing teeth, inaccordance with the present invention;

FIG. 12 is a right side elevation view of the carrier with rubblizingteeth, in accordance with the present invention;

FIG. 13 is a perspective view from the right front of the carrier withrubblizing teeth, in accordance with the present invention;

FIG. 14 is a cross-sectional view showing the rubblizing bit in use inthe renovation of a manhole, in accordance with the present invention;

FIG. 15 is a top plan view of an alternative attachment of the carrierof the rubblizing teeth to the central core of the rubblizing bit, inaccordance with the present invention;

FIG. 16 is a front elevation view of the right half of the rubblizingbit with the carrier welded to the top of the central core of the bit,in accordance with the present invention;

FIG. 17 is a top plan view of an alternate attachment of the rubblizingteeth carrier to the central core of the rubblizing bit, in accordancewith the present invention;

FIG. 18 is a elevation view of the right half of the rubblizing bit ofFIG. 17 with the carrier attached to the central core, in accordancewith the present invention;

FIG. 19 is a left side elevation view in schematic of a vacuum truck, inaccordance with the present invention;

FIG. 20 is a top plan view in schematic of the vacuum truck, inaccordance with the present invention;

FIG. 21 is a perspective view of the prior art form and apparatus asused in accordance with this invention;

FIG. 22 is a cross-sectional elevation view of the form and apparatus ofFIG. 21 in use, in accordance with the present invention;

FIG. 23 is a cross-sectional elevation view of the ring and cover at itsproper elevation with respect to the roadway with a cut T-lock step, inaccordance with the present invention;

FIG. 24 is a cross-sectional elevation view of the renovated manholewith the cover at its proper elevation with a T-lock connection to theroadway, in accordance with the present invention;

FIG. 25 is a cross-sectional elevation view of an inflatable donutshaped form of the Stehr design in use, in accordance with the presentinvention;

FIG. 26 is a cross-sectional elevation view with the manhole cover atthe proper level using the form of the Stehr design, in accordance withthe present invention;

FIG. 27 is a front elevation view of a T-lock miller or trimmer, inaccordance with the present invention;

FIG. 28 is a front elevation view, partially cut away, of the right sideof a T-lock milling bit with an alternative attachment of the carrier ofthe T-lock teeth to the central core of the bit, in accordance with thepresent invention;

FIG. 29 is a top- plan view of an elevated manhole cover at grade with aT-lock in the roadway, in accordance with the present invention;

FIG. 30 is a top plan view of an adjusting ring device for use with aninflatable donut shaped form, in accordance with the present invention;

FIG. 31 is a cross-sectional elevation view of the understructure of anew installation, in accordance with the present invention;

FIG. 32 is a perspective view of a core bit and rubblizing bit, inaccordance with the present invention;

FIG. 33 is a front elevation view of the bit of FIG. 32, in accordancewith the present invention;

FIG. 34 is a bottom plan view of the bit of FIG. 32, in accordance withthe present invention;

FIG. 35 is a perspective view of the bit attached to a prime mover, inaccordance with the present invention;

FIG. 36 is a cross-sectional view of a covered manhole cone with anexcavated hole down around the plate on the cone, in accordance with thepresent invention;

FIG. 37 is a cross-sectional view of the manhole cone with cover plateremoved and ready for installation of ring and cover, in accordance withthe present invention; and

FIG. 38 is a cross-sectional elevation view of the right rear quarter ofa trimmer bit for a T-lock or for milling in resurfacing a roadway, inaccordance with the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

Utility access covers in roadways are hardly noticeable if properlyaligned with the roadway. Proper alignment of the standard manhole coverfor sewer manholes, as required by a municipality, is shown in FIGS.1-3. This invention will be illustrated in connection with such astandard sanitary sewer manhole. However, the grinding bits and methodsare also applicable to other manholes and to smaller utility accessesthat do not require personnel access underground Also this invention isespecially useful where the underlying structure is composed of brick orother similar material and not preformed.

In the standard sanitary sewer, a sewer pipe 1 is located at the bottomof a manhole, as shown in FIGS. 1 and 2, and is positioned on a base 3.The access hole for access to the sewer pipe 1 is provided by a manholebarrel section or pipe 2, sitting above the base 3 and extending upwardtoward the roadway 4. An eccentric cone 5 is placed on top of themanhole barrel section 2 and extends up toward the road surface. Atleast one municipality limits this distance to 20 inches. The distancebetween the top surface 12 of the cone and the surface of the roadway 4typically has a standard of no greater than 24 inches. A cover 6 issupported above the cone 5 by a ring 7 and height adjusting elements 8.

In the standard sanitary sewer manhole, the manhole barrel section 2 hasan inside diameter of 4 feet and the eccentric cone 5 transitions froman inside diameter of 4 feet at the top of the barrel section 2 to aninside diameter of 2 feet at the top of the cone. Further, the barrelsection 2 and bottom of the cone 5 have a wall thickness of 5 inches.The wall thickness of the cone 5 increases to 6 inches at the top of thecone. The ring 2 comes in standard heights of 4 inches, 6 inches, 8inches, and 12 inches. The jurisdiction governing the manholespecification establishes the standard dimensions for that jurisdiction.Grand Junction, Colo., for example, requires a 6-inch high ring, whileDenver, Colo. typically requires an 8-inch high ring. The cover 6 has a24 inch or 2 foot diameter and the ring 7 has an outside diameter of 25½ inches. Ring 7 has a flange 9 near the bottom of the ring that acts asa weight supporting and locking device. When either asphalt or concreteis poured around the ring and height adjusting elements 8 it flows underand over the flange 9 to lock the ring in place. The flange 9 has aspace above the height adjusting elements 8 as the result of a mug ring17 under the flange and extending to the bottom of ring 7. Not all ringshave such mud rings. The ring adjusting elements and the top of the cone5 are encased in asphalt 10 as shown in FIG. 1 or are encased inconcrete 11 as shown in FIG. 2.

Over time the alignment of the cover 6 relative to the surface of theroadway 4 changes or may change because of deterioration in thesupporting surfaces, improperly compacted underlying material orresurfacing of the roadway which adds additional asphalt or concreteabove the height of the cover 6. The possibility of change may be notedduring routine inspections of a manhole. Sometimes, wood shims have beenused to adjust the height of the ring and cover relative to the surfaceof the roadway. This wood can and does rot out, causing a shift in thealignment of the ring and cover. Also, metal washers or other metalshims can rust out and cause shifting in the alignment of the ring andcover. Another reason for misalignment of a ring and cover of a manholeis settlement around the ring and cover due to lack of proper compactionat the time of installation. Further, the roadway surface around thecover 6 often times deteriorates because of aging and weather. If cracksform in the material around the cover, moisture can penetrate down intothe cracks. Chunks of material can be dislodged, especially wherefreezing takes place, resulting in holes around the cover 6. The cover6, being below the surface of the roadway 4 is shown in FIG. 4. Thecover below the surface in FIG. 4 is illustrative only of misalignment.The distance down can be as much as 4 inches or more when the roadway isresurfaced. Also, the cover can tilt relative to the surface of theroadway. Cracks 14 and chips 15 around the cover 6 are shown in FIG. 5.These conditions require renovation of the manhole.

Renovation requires removal of the material around the cover 6 and ring7 at least down to the flange 9 of the ring 7. This material is easilyremoved by using the rubblizing bit of this invention and sucking outthe rubble with a vacuum. The rubblizing bit provides easy breaking upof the material into small pieces about the size of one and one-halfinch gravel so that the material may be easily sucked out by a vacuum.

As an example of the efficacy of the rubblizing bit and the method ofthis invention, there were 47 manholes requiring renovation in about 3miles of roadway. Bids to do the renovation employing the old system ofjackhammers and shovels, covered a range of approximately$40,000-$90,000. The bid using the rubblizing bit of this invention andthe method of this invention was about $23,000. The apparatus and methodof this invention is much faster in setting manhole covers to grade andthree to four times as many or more can be set in a normal workday withless labor.

The detail and use of the rubblizing bit for the illustrative sanitarysewer manhole is illustrated FIGS. 6-18. In FIG. 6, the rubblizing bit20 is shown in housing 21 attached to a skidster 22, partially shown inFIG. 6. The rubblizing bit 20 and housing 21 may be attached to othermotorized vehicles or prime movers that provide means for controllingthe position of the rubblizing bit and the operation of the bit. Asnoted above, the prime mover may be any device that provides power tomove the bit and rotate the bit. The housing 21 is attached to theskidster 22 by a coupler 23 and by hydraulic hoses 24. The hydraulichoses 24 provide means for controlling the up and down operation of therubblizing bit 20 and for rotating the bit when desired. Housing 21 haslegs 25, which stabilize the position of the rubblizing bit 20. A safetyscreen can be connected between the legs 25 around the housing 21 toprevent chunks of material from flying beyond the housing 21.

The rubblizing bit 20 has a cylindrical central core 30 that is open atthe bottom and closed at the top 36 as show in FIGS. 7-10. The centralcore 30 has a wall 31 and a surface 35 at the bottom of the wall 31.Teeth 32, FIG. 8 (These teeth are also numbered 38 in FIGS. 10 and 14)are attached to the bottom surface 35 between the inner diameter 33 ofthe wall 31 and the outer diameter 34 of the wall 31. The wall 31 is ½inches thick and the central core 30 is made of steel to providerigidity and durability.

The rubblizing bit 20 further includes a plurality of carriers 40 thatare attached to the central core 30. As seen in FIGS. 12 and 13 thecarrier 40 has an upper mounting plate 41 that is attached to thecentral core 30 by one of various means. As shown in FIG. 8, themounting plate 41 is welded to the inside surface of the top of thecentral core 30. The plate 41 is welded, as shown by the bead lines 43,to the top 36 (FIG. 8). The carrier 40 has an attachment plate 44 at thebottom, which carries the rubblizing teeth for the bit. The attachmentplate 44 is spaced a distance from the mounting plate 41, determined bya vertical plate 45 that connects between the mounting plate 41 andattachment plate 44. The carrier 40 is strengthened by two triangularplates positioned between the attachment plate 44 and vertical plate 45.The strengthening plates 46 and 47 have right angles with the edges 48attached to the front surface of vertical plate 45 and edges 49 attachedto the top surface of attachment plate 44.

The attachment plate 44 has an outer curved surface 50 that matches theouter curved surface of the central core 30 and has a radius thatextends from the central axis of the central core 30. This radius may beany desired length determined by the size of hole around the ring to beexcavated by the bit and vacuum. A leading edge 51 and trailing edge 52of the attachment plate are not at right angles to the vertical plate45, but rather are at obtuse angles to the vertical plate 45. There areseveral rows of rubblizing teeth attached to the bottom of theattachment plate 44. The first row of rubblizing teeth 54 are a pair ofteeth on a radius that is one-half inch shorter than the radius for theouter curved surface 50, which is 19½ inches from the center of core 30.A second row of a pair of rubblizing teeth 55 are attached to the bottomsurface of the attachment plate on a radius that is two inches shorterthan the radius of the outer curved surface 50. Three additional teeth56, 57 and 58 are attached to the bottom of the attachment plate atradii that are increasingly shorter than the radius of the pair of teeth55. The teeth 56, 57 and 58 are at one depth and extend a first distancebelow the attachment plate 44. The teeth 55 are at a second depth andextend further from the bottom of the attachment plate 44 than the teeth56, 57, and 58. The outside row 54 of rubblizing teeth extend thedeepest relative to the bottom of the attachment plate 44. The teeth 55can be attached to a first step in the attachment plate 44 or to aseparate lowering plate 59 as shown in FIG. 12. To get the pair of teeth54 at a depth greater than the pair of teeth 55, the teeth 54 areattached to the lowering plate 59 with an additional lowering bushing60. The rubblizing teeth attached to the bottom of attachment plate 44are tilted toward the leading edge 51 to contact and rubblize thematerial as the grinding bit is rotated into the ground. Further, theoutside pair of teeth 54 are angled out beyond the outer curved surface50 to contact the material to be rubblized and removed before surface 50contacts the material.

When the carrier is mounted on the central core 30, the bottom ofattachment plate 44 is above the bottom of the teeth 38 that areattached to the bottom surface 35 of the central core 30. The teeth 56,57, and 58 attach to the bottom of attachment plate 44 and have tipsthat are ¼ inch above the tip of the teeth 38 on the bottom surface 35of the central core 30. The depth of the rubblizing teeth is best seenin FIGS. 10 and 12. In FIG. 10, the teeth 38 on the bottom surface 37 ofcentral core 30 extends below the teeth 56,57 and 58 attached to theattachment plate 44 of carrier 40. The tips of the pair of teeth 55extend ¼ inch below the tips of the teeth 38 and the tips of the pair ofteeth 54 extend 1 inch below the tips of the teeth 38. All of the teethhave a hardened steel body and a carbide tip.

The rubblizing teeth carrier of FIGS. 6-10 fit in a a slot in the sideof the central core 30 of the grinding or rubblizing bit 20. Inside theslot, the mounting plate 41 is either welded to the inside top surfaceof the central core 30 (FIG. 8), or held in place between plates 27 and28 that are welded in place by weld beads 29 and 26 (FIG. 9).

The mounting plate 41 is three-fourths inches thick, attachment plate 44is five-eighths inches thick and vertical plate 45 is three-eighthsinches thick. All are made of steel plate. The mounting plate 41 istapered to easily slide into the metal plates 26 and 29 that are weldedto the top of the core 30 or into slots in the side of the core to beheld by plates or welded. At the point of attachment to the verticalplate 45, the mounting plate 41 has a width of 9 ½ inches and at the endremote from the vertical plate 45, the mounting plate 41 has a width of5 ¾ inches. The attachment plate 44 extends 6 inches outside thevertical plate 45, which has a height of 9 inches and a width of 9 ¼inches. The braces or strengthening triangles 46 and 47 are made ofthree-eighths inch steel plate and are spaced 7 inches apart against thevertical plate 45.

In an alternative embodiment, shown in FIG. 15, the mounting plate 41 ofthe carrier 40 is welded to the top surface 36 of the central core 30.The mounting plate 41 welded to the top 37 of the central core 30, isalso shown in FIG. 16. Alternatively, the mounting plates 41 may bebolted to the central core 30 as shown in FIGS. 17 and 18.

The rubblizing bit is useful where the height of the utility accesscover needs adjusting as well as where the cover does not need adjustingrelative to the surface of the roadway in which it is located. Theoperation of the bit will first be described in connection with asanitary sewer manhole where the height of the cover (lid) does not needadjusting. The first step is the setting out of traffic control devicesand if necessary, a flag person. The second step is centering therubblizing bit 20 over the manhole cover 6 and causing it to rotate asit goes down against and into the material around the cover 6 and ring7. The material is either asphalt or concrete, with roadbase below. Thecover has a diameter of 24 inches and sits in a ring that has an outsidediameter of 25 ½ inches. The inside diameter of the rubblizing bit is 27inches so that there is a three-fourths inch clearance between theoutside diameter of the ring 7 and the inside diameter of the bit 20. Asthe bit rotates and moves down around the cover 6 and ring 7, it chewsup (grinds) or rubblizes the material. The result is rubble or smallpieces the size of one and one-half inch gravel that are small enough tobe sucked out of the hole by a vacuum. The open end of a vacuum hose 64,shown in FIG. 14, is placed in the hole 18 being ground out by therubblizing drill bit 20. The rubble is sucked up through the hose 64into a vacuum tank 65, located on a truck 66 (FIGS. 19 and 20). Thevacuum can be transported on a trailer as well as on a truck. Theremoval of the rubble, while the rubblizing bit 20 is drilling the hole,makes it easier for the bit to rotate and reach the desired depth. Thedesired depth of the bit 20 is where the teeth 38 touch or engage theflange 9 of the casting or ring 7. The teeth 38 on the bottom surface 35of the cylindrical central core 30 cut into and through asphalt,concrete and roadbase, but not steel. Consequently, when the teeth 38contact the steel of flange 9 the rubblizing bit cannot descend further.The desired depth of rubblizing has been reached.

With the rubble sucked out, the bit 20 has created a hole approximately3 ⅓ feet in diameter, with the outer portion of the hole being deeperthan the inner portion established by the teeth 38 on the central coreand teeth 56-58 on the carrier 40. Teeth 54 on the outer periphery ofthe carrier 40 and teeth 55 cut down below the flange 9. In this way thebit breaks loose the flange 9 from the top of cone 5 or the heightadjusting material 8. The rubblizing bit is then pulled up out of theexcavated hole 18. The height of the cover 6 is checked and, if it is inproper position, the hole 18 is filled with either asphalt or concrete.The traffic control and equipment can then be moved to the next utilitycover to be set to grade.

There are additional steps in the method where the cover 6 and ring 7need to have a height adjustment relative to the surface of theroadbase. Sometimes when the roadbase is resurfaced, the resurfacing isdone around the manhole cover or over the manhole, leaving the coverbelow the surface of the roadway. Additionally, there are times when thesupporting structure, such as the height adjusting rings 8 or shims (notshown) have broken down and the height of the cover 6 and ring 7 arebelow the street level or at least one side is below the surface of theroadway. In all cases, the renovation includes setting the height of thering and cover to grade or aligned with the surface of the street.

First the traffic control devices are put in place and if necessary aflag person is used so that the renovation, including the adjustments ofthe height of the manhole cover may be done safely. Again, therubblizing bit 20 is centered over the manhole cover and it is caused torotate as it goes down against and into the material around the cover 6and the ring 7. Again, as the teeth 38 reach the flange 9 of the ring 7,the rubblizing bit stops and the vacuum completes the removal of therubble from hole 18. The rubblizing bit 20 is removed from the hole 18.Rubblizing or in-situ grinding of the material is more desirable thanjackhammering, which leaves large, heavy pieces of material that have tobe manhandled or machine loaded into a disposal unit.

After removal of bit 20, another bit 79 (FIG. 27), having only a centralcore 80, of the same construction as the central core 30, with teeth onthe bottom surface of the cylindrical portion of the central core, issubstituted for the rubblizing bit 20 in the housing 21 or placed inanother housing, as shown in FIG. 6. The internal diameter of thecentral core 80 of the bit of FIG. 27 is 43 inches so that it will godown and around the top portion of the cone 5 of the illustrativestandard sanitary sewer manhole, which at it's uppermost reach is 36inches in diameter, or 3 feet across. In this way the material downaround the top of the cone 5 is broken loose and sucked out by thevacuum unit 66 through hose 64. At this point the bit 79 is pulled outof the hole and the ring 7 and cover 6 are removed from the hole as wellas any height adjusting rings 8 on top of the cone 5. As noted above thebit 79, shown in FIG. 27, has an additional set of teeth used forcreating a step for a T-lock that may not be present for this operation.

The design and use of the rubblizing bit 20 is especially advantageouswhere the cone and barrel section or pipe are constructed out of brick.Because the rubblizing bit 20 stops at the flange of the ring, the bitwill not go into the underlying brick. However, in the past, cones madeof brick have been damaged by the jackhammers used in the prior artmethod.

If the distance between the bottom of the ring 7 and the top surface 12of cone 5 is greater than 2 inches, a cuttable form 30 is used toprovide the proper height for the cover 6. This form, as describedabove, is disclosed in detail in U.S. Pat. No. 5,934,820 ('820) grantedon Aug. 10, 1999 to Vernon W. Hinkle and U.S. Pat. No. 6,161,985 ('985)granted Dec. 19, 2000 to Vernon W. Hinkle and John D. Tensen. Theapparatus is disclosed in the '985 patent and the process for employingthe apparatus is covered in the '820 patent. The '820 patent and '985are incorporated herein by this reference as though set forth in full.

As shown in FIGS. 21 and 22 and described in the '820 patent, the form70 is placed in the hole 18 on top of the top surface 12 of the cone 5.The form 70 is a tubular cone that is wider at the bottom to fit on thetop surface of the cone 5 and narrower at the top to fit under the ring7. The form is comprised of a material that is strong enough to supporta concrete pour. The form 70 is stabilized on the top surface 12 of thecone 5 and a trimmer jig frame 72 is placed on the surface of theroadway and internal of the form 70 as shown in FIG. 22. The jig frame72 has a circular member 73 with horizontal tabs 74 on the outside ofthe circular member 73, which rest on the surface of the roadway towhich the cover 6 of the manhole cover is to be adjusted. The jig 72further has vertical tabs 75 on a X-shaped cross frame 76. The verticaltabs 75 fit inside the form 70 to stabilize the form 70 while it is cutto provide the precise height for the form 70 and, thus, the ring 7 andcover 6 relative to the surface of the roadway. The amount of tubularform 70 to be trimmed away by the inverted trimmer is determined bymeasuring the critical dimension of the manhole ring 7. This criticaldimension is the distance from the upper surface 13 of the ring 7 andthe bottom surface 16 of the flange 9 as shown in FIGS. 23 and 24. Acutter 77 of the trimmer 72 is then positioned to cut the form 70 at adistance from the top down that is equal to the critical distance of thering 7 between its top surface 13 and the bottom surface 16 of flange 9.Upon completion of the cutting of the form 70, the trimmer jig frame isremoved. The ring 7 is placed on top of the trimmed form 70 as shown inFIG. 23. The area around the form is filled with concrete to the bottomof flange 9, and when sufficiently cured, the balance of the hole 18 isfilled, either with concrete or asphalt.

If the hole 18 is filled with asphalt, a further feature of theinvention may be employed as shown in FIGS. 23 and 24. After therubblizing bit 20 has been removed, a bit 79 shown in FIG. 27, with alarger inside diameter central core 80 is attached and used to completethe loosening of the material around the bottom of the ring 7 and thetop of the cone 5. This bit is modified to provide a T-lock 99 thatreduces the possibility of moisture getting down into the area of themanhole. This bit also removes any elevated road material at the edge ofthe hole. Carriers 81 for a T-lock trimmer 86 (milling bit) is attachedto the central core 80 of the larger circumference bit 79 as show inFIG. 27. Carrier 81 has a mounting plate 82 that fits in a slot 83 inthe side of the central core 80. The mounting plate 82 also extendsbeyond the circumference of the central core 80 by 6 inches to provide afurther cut or step 90 (FIG. 23) in the road surface. When the hole 18and step 90 are filled with asphalt as shown in FIG. 24, a T-lock 99results. The teeth of the trimmer 86 create ridges on the horizontalsurface of step 90. Tack oil is placed on the horizontal surface beforelaying down the asphalt to create a barrier to moisture.

Teeth 85 are attached to the bottom surface of the mounting plate 82 andcut away or grind the surface of the roadway 4 as the bit 79 goes downinto the hole 18 and forms the cut or step 90 in the existing asphalt orconcrete surface. There are 3 carriers 81 located 120 degrees apartaround the central core 80. The front carrier 81 is not shown in FIG.27.

The T-lock trimmer 86 may have an alternative means of attachment to thecentral core 80 as shown in FIG. 28. In this case the carrier 91 for theT-lock teeth has a step 92 to have the teeth 93 at the desired depthwith respect to the surface of the roadway 4. Carrier 91 has anattachment plate 94 for the teeth 93 and a mounting plate 95, both ofwhich are horizontal relative to the vertical member 96. Vertical plate96 provides a step of selected distance between attachment plate 94 andmounting plate 95. In a 3 inch thick asphalt or concrete surface, thecut 90 will be 1 ½ inches deep to provide the T-lock. The depth andwidth of the T-lock may vary depending upon the material and roadconditions. Additionally, the central core 80 may have a short height,such as 6 inches, and no teeth on the bottom surface. In this case, thebit will only function as a trimmer bit.

If the distance between the bottom of ring 7 and the top surface 12 ofcone 5 is less than 2 inches, then an inflatable donut shaped form 100is employed as shown in FIG. 26. A means for positioning and orientingthe top of the ring 7 relative to the surface of the roadway isavailable form Mountain Valley Equipment and is manufactured by StehrBaumaschinen GmbH, This device is called an Adjustable Ring and LevelingRule 98. This device (shown in FIG. 25) has three arms 104 (FIG. 30)that extend out from a center piece 103 to lie on the surface of theroadway 4. Additionally, the Adjustable Ring has a means for holding thering 7 consisting of clamps 107 in cooperation with adjustable clamp105. The clamp 105 has a movable arm that extends down into the ringwhere the cover will be positioned. This arm, when moved by handle 108forces the ring 7 against the stationary clamps 107 to hold it in place.

The ring 7 is attached to the Adjusting Ring 98 and the combination isplaced over the cone 5 with the arms 104 lying on the surface of theroadway with adjustable feet 102. The altitude or position of the top ofthe ring 7 is adjusted by use of a level and the feet 102. Once the topof ring 7 is on grade with the roadway, an inflatable doughnut shapedform 100 is placed inside the ring 7 and inside the top of cone 5 asshown in FIG. 26.

Straps 106 extend up from form 100 and one strap is placed over thehandle 108 of adjustable clamp 105. The form is then inflated to fillthe space between the bottom of ring 7 and the top surface 12 of cone 5to provide a surface 110 that holds out the concrete poured around theform 100 and bottom of the ring 7. The inflated form 100 seals againstthe bottom inside surface of ring 7 and the top inside surface of cone 5to prevent seepage into cone 5 of the grout or concrete that is pouredinto the hole up to the top of flange 9. When the concrete is cured, thedoughnut shaped form 100 is deflated and removed. The remainder of thehole is then filled with concrete or asphalt and the cover 6 is put intoplace.

Another occasion where the cover and ring of a manhole are involved iswhere they are at grade with the present surface of the roadway and theroadway is to be resurfaced. Generally, old road material is milled downso that a new layer of material may be laid down to result in the samesurface level. In the past, it has taken considerable time to millaround each ring and cover of the manholes in the street. This has beendone with milling brushes on prime movers, such as skidsters, by scoopson skidsters or backhoes, or with jackhammers and shovels. A moreefficient and faster way is to employ a trimmer 112 shown in FIG. 38,with a central core. The central core may have teeth at the bottom, asshown in FIG. 38, or may be just a carrier for the trimming or millingteeth 115. There are a plurality of carriers 114 with trimming ormilling teeth 115 attached to an attachment plate 116. The attachmentplate and teeth extend out 12 inches from the outside surface of thecentral core. This distance may be more or less depending upon how closethe large milling equipment is able to get to the access hole. Themilling around each manhole may be done before or after the milling ofthe street.

The central core has an inside diameter of 27 inches for the standardsanitary sewer manhole cover and ring. The carrier 114 (FIG. 38) has anattachment plate 116 that extends 12 inches beyond the outside diameterof the central core 113. A plurality of teeth 115 are attached to thebottom of the attachment plate 116. The trimmer 112 is attached to aprime mover, such as a skidster, for positioning and rotation. Theheight of the central core 113 is 6 inches from the top 117 of the core113 to the tip of the teeth 118 at the bottom of the central core 113.This height only has to be sufficient to cut down 1½ inches for thetypical roadway.

The carrier 114 has a mounting plate 119 that is slid into a slot in theside of the central core 113 and is held in place by plates (not shown)and welded to the inside of the top 117. The plate 119 may also bewelded to the top 117 of the core 113 or bolted in the sot or on top.

The bit without attachments is useful in setting the ring and cover innew installations. These new installations may be of small access coversor large access covers, such as used for manholes.

In a new installation, as illustratively shown for a manhole in FIG. 31,other cone and other understructure is in place when the roadway is putdown. The cone 5 is covered with a plate 120 and is covered withcompacted roadbase material 121. The roadway 122 is then laid over thecone 5 and plate 120.

The cone 5, shown in FIG. 31 is a cross-sectional view that is rotated90 degrees from the cross-sectional views of FIGS. 1, 2, 4, 14, 22-26.The cone is eccentric and has a surface 123 that is relatively flat forattachment of an access ladder.

The location of the covered cone under the roadway is generally markedby two or more marks on the curb or the side of the roadway.Intersecting arcs are used to locate the center of the cone.

Once the center of the cone is determined, a core bit 124, as shown inFIGS. 32 and 35, is centered over the cone. This core bit 124 hasexterior flanges 125 that curve from the bottom of the bit to its top toassist in bringing up the ground up roadway and roadbase. StehrBaumaschinen GmbH has made a core bit without these flanges 125. Stehrnow makes a core bit with flanges that are available from MountainValley Equipment. The core bit is also shown in FIGS. 33 and 34 withoutthe flanges 125.

The core bit is used to cut a circular plug (not shown), out of theroadway. This plug is moved out of the circular hole cut by bit 124. Theplug may be moved by a scoop on a skidster or by some other means. Afterremoval of the plug, the underlying material is sucked out by vacuum.

If the material is too tightly compacted, a small jackhammer is suppliedby pressurized air from a compressor (not shown) mounted on the vacuumtruck 66 (FIGS. 19 and 20) and is used to loosen the material. In anyevent, the material is sucked out by vacuum to significantly speed upthe process of setting the new ring and cover. Once the hole 126 isevacuated down to the top of the cone 5, the plate 120 is removed.

The distance 127 from the top of the cone 5 to the surface of theroadway 122 is determined. Based upon the distance, an adjustable heightform, such as the Whirlygig or the inflatable donut is selected for usein setting the ring and cover to grade.

The bit of FIGS. 32 and 35 does not have a carrier for rubblizing teethor a carrier for milling a step for a T-lock or a carrier for milling ortrimming around a utility access cover.

The core bit of FIGS. 32 and 35, depending upon its dimensions andattachments, has many uses. One use is rubblizing down to the cone areaof a manhole after a rubblizing bit has rubblized down to and around theflange of the ring. Another use is the rubblizing with carriers ofrubblizing teeth attached to and carried by the central core. A furtheruse is for milling a step in the roadway for a T-lock when milling ortrimming teeth carriers are attached. For this purpose the central coremay have a very short height and no teeth on the bottom surface 35 or itmay have a height of 12 inches or more or less with the milling teethnear the top and teeth 38 on the bottom surface 35. Also, where thetrimming teeth are for milling or trimming the surface around a utilityaccess cover during resurfacing, the inside diameter of the cone isslightly greater than the outside diameter of the ring. The teeth 38 atthe bottom of the core 30 grind down around the ring and stabilizes andpositions the trimmer. The teeth on the trimmer carrier extend out 12inches or another selected distance to mill around the ring forresurfacing of the roadway area around the access hole.

Although the description above contains specificity, this should not beconstrued as limiting the scope of the invention, but merely asproviding illustrations of one of the presently preferred embodiments ofthe invention. Although preferred embodiments and method for renovatingmanholes have been described above, the invention is not limited to thespecific embodiments, but rather the scope of the invention is to bedetermined as claimed.

1. A rotary bit for rubblizing the material around a utility accesscover and ring down to the flange of the ring by rotary grinding,comprising a cylindrical central core having an inside diameter that islarger than the outside diameter of the ring and at least one carrierhaving an attachment surface that is perpendicular to the outsidesurface of the cylindrical central core and extending beyond the outsidediameter of the central core with a plurality of rubblizing teethattached to and extending below the attachment surface.
 2. A bit inaccordance with claim 1 wherein some of the rubblizing teeth extendbelow the flange when the bit is in contact with the flange.
 3. A bit inaccordance with claim 2 wherein the carrier comprises a mounting plateat the top for attaching to the central core, a vertical plate thatextends down the outside surface of the cylindrical central core, and anattachment plate extending out at a 90° angle from the vertical platenear the bottom on the central core and providing the attachment surfacefor the teeth.
 4. (canceled)
 5. (canceled)
 6. (canceled)
 7. A bit inaccordance with claim 3 wherein the plurality of teeth include a firstrow of teeth mounted near the outside edge of the attachment plate andangled forward toward the direction of rotation of the bit and angledoutwardly with the tips of the teeth extending beyond the outer edge ofthe attachment plate.
 8. A bit in accordance with claim 7 wherein theplurality of teeth include a second row of teeth inside the outside rowof teeth and having tips above the tips of the outside row.
 9. A bit inaccordance with claim 8 wherein teeth are attached to the bottom of theattachment plate between the second row and the central core.
 10. A bitin accordance with claim 9 wherein the central core is open at thebottom and has a surface around the bottom and further comprising aplurality of teeth attached to the surface.
 11. A bit in accordance withclaim 10 wherein the tips of the teeth in the second row extend belowthe tips of the teeth on the bottom surface of the central core and thetips of the teeth of the first row extend below the tips of the teeth inthe second row.
 12. A rotary bit for rubblizing the material below theflange of the ring of a manhole and down to below the top of the cone ofthe manhole comprising a cylindrical central core having teeth on asurface at the bottom of the cylinder, the central core having an insidediameter that is greater than the outside diameter of the cone, aplurality of carriers, each having a horizontal attachment plateextending out from the vertical cylindrical surface of the central coreand positioned at a selected distance from the top of the central core,a plurality of teeth attached to the underside of the attachment platefor grinding a step in the surface of the roadway beyond the outsidediameter of the central core.
 13. A rotary bit having a cylindricalcentral core with an outside surface and open at the bottom, anattachment plate extending a selected distance beyond the outsidediameter of the central core and at a 90° angle to the outside surfaceof the cylindrical core, and a plurality of teeth attached to theunderside of the attachment plate.
 14. A bit in accordance with claim 13further comprising teeth on the bottom surface of the central core togrind into the material around the ring to stabilize the bit in use. 15.A bit in accordance with claim 14 wherein the selected distance is 12inches.
 16. The method of setting manhole covers, the manhole having acone, a ring and a cover, comprising the steps of rubblizing thematerial around the ring and cover by a rotary grinder and removing therubblized material by a vacuum machine to form an excavated area aroundthe ring.
 17. The method in accordance with claim 16 wherein thegrinding rubblizes the material down to at least the flange of the ring.18. The method in accordance with claim 16 wherein the rubble is removedwhile the grinding is taking place.
 19. The method in accordance withclaim 17 comprising the further step of grinding down below the topsurface of the cone to rubblize the material below the materialrubblized in the first rubblizing step.
 20. The method in accordancewith claim 19 further comprising the step of removing the rubblizedmaterial below the material rubblized in the first rubblizing step. 21.The method in accordance with claim 20 wherein the rubblized material isremoved by sucking up the material with a vacuum.
 22. The method inaccordance with claim 20 comprising the further step of removing thering, cover and any height adjusting material from the excavated hole.23. The method in accordance with claim 22 comprising the further steps,determining the distance between the top surface of the ring and thebottom surface of the flange on the ring, inserting a height adjustingform on the top surface of the cone, placing a cutter inside the formwith the depth of the cutter referenced to the surface of the roadway,cutting the form at a height determined to place the top of the ringaligned with the surface of the roadway, removing the cutter and the topcut portion of the form, inserting the ring and cover on top of the formand filling the evacuated area around the top of the cone, form and ringto the surface of the roadway.
 24. The method of claim 23 wherein thefilling steps include pouring concrete into the area up to the level ofthe bottom of the flange and filling the rest of the area with asphalt.25. The method in accordance with claim 23 wherein the area is filledwith concrete to the surface of the roadway.
 26. The method inaccordance with claim 23 wherein the area is filled with asphalt to thesurface of the roadway.
 27. The method in accordance with claim 16further comprising the step of milling the road surface to a selecteddepth and out a selected distance from the outside diameter of the hole.28. The method in accordance with claim 27 wherein the milling isperformed during the step of drilling down beyond the top of the cone.29. The method of claim 27 comprising the further step of filling thearea milled with the same material as the roadway.
 30. The method ofmilling around an access ring and cover comprising the steps of grindinga hole around the ring to stabilize and position the milling bit andmilling out a selected distance and depth by grinding the material witha rotating bit.
 31. Apparatus for setting utility covers comprising arubblizing bit as means for grinding the material into small piecesaround the utility access cover and ring and down to a selected depthand means for sucking out the small pieces.
 32. A trimmer bit formilling around a ring and cover of a utility access for resurfacing theroadway around the access comprising a central core with teeth toposition and stabilize the trimmer and teeth attached to an attachmentplate extending out a selected distance from the core.
 33. The method ofremoving the material above a cone of a manhole comprising the steps ofrubblizing the material above the cone and out a selected distancebeyond the outer periphery of the top of the cone and removing therubblized material by a vacuum machine.